U.S. patent number 6,141,580 [Application Number 09/209,604] was granted by the patent office on 2000-10-31 for detecting coil for magnetic resonance diagnostic apparatus.
This patent grant is currently assigned to GE Yokogawa Medical Systems, Limited. Invention is credited to Yujiro Hayashi, Masaaki Sakuma.
United States Patent |
6,141,580 |
Hayashi , et al. |
October 31, 2000 |
Detecting coil for magnetic resonance diagnostic apparatus
Abstract
In order not to nip the clothes or skin of a subject between the
joining portions of coil members when a detecting coil for a
magnetic resonance diagnostic apparatus is fitted around a region
of the subject such as the leg or neck, the detecting coil 100 for
a magnetic resonance diagnostic apparatus, which can be separated
into an upper coil member 10 and a lower coil member 20 and has an
annular shape when these members 10, 20 are integrally joined, is
provided at the joining portions of the lower coil member 20 with
guards 27, 28 of a silicone rubber having a hardness of Hs80.
Inventors: |
Hayashi; Yujiro (Tokyo,
JP), Sakuma; Masaaki (Tokyo, JP) |
Assignee: |
GE Yokogawa Medical Systems,
Limited (Tokyo, JP)
|
Family
ID: |
18464267 |
Appl.
No.: |
09/209,604 |
Filed: |
December 11, 1998 |
Foreign Application Priority Data
|
|
|
|
|
Dec 26, 1997 [JP] |
|
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9-359390 |
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Current U.S.
Class: |
600/422;
324/318 |
Current CPC
Class: |
G01R
33/34046 (20130101); G01R 33/341 (20130101); G01R
33/34084 (20130101) |
Current International
Class: |
G01R
33/34 (20060101); A61B 005/055 () |
Field of
Search: |
;600/422,421
;324/307,309,318,322 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Lateef; Marvin M.
Assistant Examiner: Mercader; Eleni Mantis
Attorney, Agent or Firm: Kojima; Moonray
Claims
What is claimed is:
1. In a coil assembly for MR diagnostic apparatus comprising:
a pair of annular coil members; and
connecting means for connecting the pair of annular coil members to
form a hollow cylindrical or annular shape thereof; the improvement
wherein
said connecting means comprises a guard portion extending an axial
length of an inside diameter of each of two ends of one of said
pair of annular coil members and above the face of said two ends;
and wherein
corresponding ends of the other of said pair of annular coil
members have connecting portions removed from surfaces of said ends
of said other pair of annular coil members so that in a closed
state the pair of annular coil members are fitted together smoothly
with the spaces between the ends of both annular coil members being
covered by said guard portions.
2. The coil assembly of claim 1, wherein the ends of both of said
annular coil members have inter-locking connections thereon.
3. The coil assembly of claim 1, wherein said guard portions are
cut obliquely, and a surface of the other of said pair of annular
coil members is correspondingly cut obliquely at the ends
thereof.
4. The coil assembly of claim 1, wherein connector means are
disposed on the ends of one coil member and corresponding holes are
formed on the other ends of the other coil member so that in a
closed state, the connector means are engaged in said corresponding
holes.
5. The coil assembly of claim 1, wherein said guard portions
comprise an elastomer of hardness JIS Hs50-Hs80.
Description
BACKGROUND OF THE INVENTION
The present invention relates to a detecting coil for a magnetic
resonance (MR) diagnostic apparatus, and more particularly, to such
a coil which is improved so as not to nip the clothes or skin of a
subject between the joining portions of coil members when the coil
is fitted around a region of the subject such as the leg or
neck.
Japanese Patent Application Laid Open No's. 4-354934(1992) and
6-254068(1994) disclose an RF (radio frequency) coil for an MR
imaging apparatus which can be separated into an upper structure
and a lower structure and is cylindrically shaped when these
structures are integrally joined.
The split detecting coil as disclosed in the above applications is
formed so that the coil is in close contact with the region of the
subject to be examined such as the leg or neck, in order to
efficiently receive an MR signal.
This implies, however, that the coil affords no spatial leeway. The
coil members are therefore liable to nip the clothes or skin of the
subject between their joining portions when they are integrally
joined around the region such as the leg or neck of the
subject.
SUMMARY OF THE INVENTION
It is therefore an object of the present invention to provide a
detecting coil for an MR diagnostic apparatus which is improved so
as not to nip the clothes or skin of a subject between the joining
portions of coil members when the coil is fitted around a region of
the subject such as the leg or neck.
In accordance with a first aspect, the present invention provides a
detecting coil for an MR diagnostic apparatus which consists of two
or more coil members and has a cylindrical or annular shape when
the coil members are integrally joined, wherein a part or the
entirety of each joining portion of the two or more coil members is
provided with an elastomeric guard portion.
According to the detecting coil for an MR diagnostic apparatus of
the first aspect, catching of the clothes and skin of a subject
between the joining portions of the coil members is made unlikely
by the cushioning effect of the guard portions. The clothes and
skin of the subject are thus prevented from being nipped when the
coil is fitted around the region such as the leg or neck of the
subject.
The present invention provides an additional advantage that the
coil member is protected from damage when accidentally dropped or
bumped against a table etc., because the shock is absorbed by the
cushioning effect of the guard portion.
Elastomer materials usable in the present invention include:
silicone rubbers, nitrile rubbers, fluororubbers, chloroprene
rubbers, polyurethane rubbers, butyl rubbers, Thiokol rubbers,
polybutadiene rubbers and styrene-butadiene rubbers.
In accordance with a second aspect, the present invention provides
the detecting coil for an MR diagnostic apparatus of the foregoing
structure, wherein the hardness of the elastomer as determined by
the JIS spring hardness test is Hs50-Hs80.
The inventors' studies show that when the hardness of the elastomer
as determined by the JIS spring hardness test is less than Hs50,
the guard portion is too soft and poor in durability, and when it
is more than Hs80, the guard portion is too hard and is difficult
to mold. A hardness in the range of from Hs50 to Hs80 inclusive
provides moderate cushioning properties and is preferred.
Thus, according to the detecting coil for an MR diagnostic
apparatus of the present invention, the likelihood of the clothes
and skin of a subject being caught between the joining portions of
the coil members is greatly reduced by the cushioning effect of the
guard portions, thereby preventing the clothes and skin of the
subject from being nipped between the joining portions of the coil
members. Moreover, the coil member is protected from damage when
accidentally dropped or bumped, because the shock is absorbed by
the cushioning effect of the guard portion.
Further objects and advantages of the present invention will be
apparent from the following description of the preferred
embodiments of the invention as illustrated in the accompanying
drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is an exploded perspective view of a detecting coil for an
MR diagnostic apparatus in accordance with a first embodiment of
the present invention.
FIG. 2 is a perspective view of the detecting coil for an MR
diagnostic apparatus in accordance with the first embodiment in the
assembled state.
FIG. 3 is a front elevational view of the detecting coil for an MR
diagnostic apparatus in accordance with the first embodiment.
FIG. 4 is a rear elevational view of the detecting coil for an MR
diagnostic apparatus in accordance with the first embodiment.
FIG. 5 is a top plan view of the detecting coil for an MR
diagnostic apparatus in accordance with the first embodiment.
FIG. 6 is a bottom plan view of the detecting coil for an MR
diagnostic apparatus in accordance with the first embodiment.
FIG. 7 is a left side view of the detecting coil for an MR
diagnostic apparatus in accordance with the first embodiment.
FIG. 8 is a right side view of the detecting coil for an MR
diagnostic apparatus in accordance with the first embodiment.
FIG. 9 is a right side view of the detecting coil for an MR
diagnostic apparatus in accordance with the first embodiment.
FIG. 10 is an exploded perspective view of a detecting coil for an
MR diagnostic apparatus in accordance with a second embodiment of
the present invention.
FIG. 11 is a perspective view of a detecting coil for an MR
diagnostic apparatus in accordance with a third embodiment of the
present invention.
DETAILED DESCRIPTION OF THE INVENTION
Preferred embodiments of the present invention will now be
described in detail with reference to the accompanying
drawings.
First Embodiment
FIG. 1 is an exploded perspective view of a detecting coil for an
MR diagnostic apparatus in accordance with a first embodiment of
the present invention.
The detecting coil 100 for an MR diagnostic apparatus consists of a
semi-annular upper coil member 10 and a semi-annular lower coil
member 20.
The upper coil member 10 is covered with covers 11, 12 of urethane
resin, and has connectors 13, 14 and locking levers 15, 16 at its
joining portions.
The lower coil member 20 is covered with covers 21, 22 of urethane
resin, and has connectors 23, 24 and locking concavities 25, 26 at
its joining portions.
At the joining portions of the lower coil member 20 are further
provided guards 27, 28 of a silicone rubber having a hardness of
Hs80. The guards 27, 28 protrude upwardly about 15 mm above the
surfaces of the connectors 23, 24. The outer ends of the guards 27,
28 are cut obliquely.
Reference symbol `a` designates a hole for a signal cable, `b1`
designates a registration mark to which an alignment laser beam is
adjusted when the coil is used for a subject raised up (e.g., in
imaging the neck region), `b2` and `b3` each designates a
registration mark to which the alignment laser beam is adjusted
when the coil is used rotated 45 degrees (e.g., in imaging the knee
region), and `c1` and `c2` each designates an alignment mark for
orienting the upper coil member 10 and the lower coil member
20.
FIG. 2 is a perspective view showing the upper coil member 10 and
the lower coil member 20 integrally joined to form the annular
detecting coil 100 for an MR diagnostic apparatus.
FIG. 3 is a front elevational view, FIG. 4 is a rear elevational
view, FIG. 5 is a top plan view, FIG. 6 is a bottom plan view, FIG.
7 is a left side view, and FIG. 8 is a right side view, of the
detecting coil 100 for an MR diagnostic apparatus.
FIG. 9 illustrates the detecting coil 100 of an MR diagnostic
apparatus
being fitted around the neck of a subject.
The lower coil member 20 is disposed in a space between a bed B and
the neck of the subject H lying thereon. The upper coil member 10
is then integrally joined with the lower coil member 20 so that it
covers the neck of the subject H. This helps to prevent the clothes
and skin of the subject H from resting on the joining portions of
the lower coil member 20 because the guards 27, 28 protrude from
the joining portions of the lower coil member 20. The clothes and
skin of the subject H can be thus prevented from being nipped
between the lower coil member 20 and the upper coil member 10.
Since the outer ends of the guards 27, 28 are cut obliquely, the
guards 27, 28 serve also as guides for the joining.
Moreover, the lower coil member 20 is protected from damage to the
connectors 23, 24 etc. when it is accidentally dropped or bumped
against a table etc., because the shock is absorbed by the
cushioning effect of the guards 27, 28.
Second Embodiment
FIG. 10 is an exploded perspective view of a detecting coil for an
MR diagnostic apparatus in accordance with a second embodiment of
the present invention.
The detecting coil 100A for an MR diagnostic apparatus consists of
a semi-annular upper coil member 10A and a pedestal-like lower coil
member 20A, and is used for limb imaging.
The lower coil member 20A is provided at its joining portions with
a connector 23A etc., and guards 27A, 28A of a silicone rubber
having a hardness of Hs80.
Third Embodiment
FIG. 11 is a perspective view of a detecting coil for an MR
diagnostic apparatus in accordance with a third embodiment of the
present invention.
The detecting coil 100B for an MR diagnostic apparatus consists of
a semi-annular upper coil member 10B and a pedestal-like lower coil
member 20B, and is used for imaging the head region.
The upper coil member 10B and the lower coil member 20B are
pivotally attached to each other at their respective ends, and the
other ends are configured to be opened and closed. At the joining
portions on the side of the open-and-close ends are provided a
connector 23B etc., and guards 27B, 28B of a silicone rubber having
a hardness of Hs80.
Many widely different embodiments of the invention may be
configured without departing from the spirit and the scope of the
present invention. It should be understood that the present
invention is not limited to the specific embodiments described in
the specification, except as defined in the appended claims.
* * * * *